Question

A bag contains white and black balls. The ratio of the white and black balls is 4 ∶ 7. If the number of black balls is 280, then find the number of white balls in the bag.
1. 120
2. 80
3. 160
4. 200

Answer 1

Correct Answer - Option 3 : 160

Given:

Ratio of white and black balls is 4 : 7

Number of black balls is 280

Calculation:

Let say number of white balls be 4x,

Then number of black will be 7x,

According to the question,

⇒ 7x = 280

⇒ x = 280/7

⇒ x = 40

Number of white ball,

⇒ 4x = 4 × 40

⇒ 160

∴ The number of white balls is 160.